Ultra-high molecular weight polyethylene fused yarn

ABSTRACT

A fused yarn ( 1 ) including an ultra-high molecular weight polyethylene multifilament contains a liquid paraffin having an average molecular weight of 400 or more in an amount 15% by weight or more. The ultra-high molecular weight polyethylene fused yarn ( 1 ) of the present invention is excellent in fusibility.

TECHNICAL FIELD

The present invention relates to a fused yarn in which a plurality of ultra-high molecular weight polyethylene filaments are fused.

BACKGROUND ART

As yarns used for fishing materials such as fishing lines and fishing nets, ropes, and racket strings, monofilament yarns and multifilament yarns formed of a plurality of monofilaments have been known.

For example, the monofilament yarn has excellent surface smoothness and low frictional resistance. Therefore, when the monofilament yarn is used as a fishing line, a fishing tackle can be cast far away. Furthermore, since the monofilament yarn does not hold water inside, water may be drained. However, since the monofilament yarn generally has high rigidity, the thicker the monofilament yarn, the lower the flexibility, and the monofilament yarn thus becomes difficult to be used as a fishing line. Particularly, the ultra-high molecular weight polyethylene filament has high strength, but it has a problem that it is difficult to handle because it is difficult to manufacture in proportion to the thickness and the rigidity is increased.

On the other hand, the multifilament yarn becomes a yarn having a desired thickness and excellent flexibility by appropriately setting the number and thickness of monofilaments. Therefore, the multifilament yarn is easy to handle, and can be suitably used, for example, as a fishing line. In particular, the ultra-high molecular weight polyethylene multifilament yarn has an advantage that it is easy to handle while having high strength. However, the ultra-high molecular weight polyethylene multifilament yarn has a problem that water is not easily drained because water is easily held inside the yarn. Furthermore, the ultra-high molecular weight polyethylene multifilament yarn has a problem that the filament at a cut portion may be separated and become fluffy. The term “separated” means that a group is divided into a plurality of groups.

A multifilament yarn having a form like a single yarn such as a monofilament yarn has good water drainage and can also prevent filament separation. Hereinafter, a form like a single yarn such as a monofilament yarn is referred to as “monofilament shape”.

In order to solve such a problem of the ultra-high molecular weight polyethylene multifilament yarn, an ultra-high molecular weight polyethylene fused yarn in which each monofilament of the multifilament is fused has been known (Patent Documents 1 to 4).

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent No. 3669527

Patent Document 2: Japanese Patent Laid-open Publication No. JP 2008-75239 A

Patent Document 3: Japanese Patent Laid-open Publication No. JP 2019-31754 A

Patent Document 4: Japanese Patent Laid-open Publication No. JP 2008-517168 W

SUMMARY OF THE INVENTION

However, an ultra-high molecular weight polyethylene fused yarn in which each filament is sufficiently fused has not yet been provided. Furthermore, a fishing line used by being knotted in a fishing tackle is required to have a high knot strength. Therefore, it is desired to provide an ultra-high molecular weight polyethylene fused yarn that is excellent in fusibility so that each filament is not separated and is excellent in knot strength.

PROBLEMS TO BE SOLVED BY THE INVENTION

A first object of the present invention is to provide an ultra-high molecular weight polyethylene fused yarn which is excellent in fusibility.

A second object of the present invention is to provide an ultra-high molecular weight polyethylene fused yarn which is excellent in knot strength.

SOLUTIONS TO THE PROBLEMS

For the above purposes, the present inventors have studied substances that promote or assist fusion of an ultra-high molecular weight polyethylene multifilament from various angles. As a result of many experiments, it was found that the above objects could be achieved by using a predetermined amount of a liquid paraffin having a predetermined molecular weight.

An ultra-high molecular weight polyethylene fused yarn of the present invention includes an ultra-high molecular weight polyethylene multifilament, wherein the fused yarn includes a liquid paraffin having an average molecular weight of 400 or more in an amount of 15% by weight or more.

In a preferred ultra-high molecular weight polyethylene fused yarn of the present invention, the liquid paraffin has an average molecular weight of 430 or more.

In a preferred ultra-high molecular weight polyethylene fused yarn of the present invention, the liquid paraffin has an average molecular weight of 450 or more and 490 or less.

In a preferred ultra-high molecular weight polyethylene fused yarn of the present invention, a single yarn fineness of the fused yarn is 0.7 dtex or more and 2.5 dtex or less.

In a preferred ultra-high molecular weight polyethylene fused yarn of the present invention, the fused yarn is twisted with a twist coefficient of more than 0 and 2,200 or less.

In a preferred ultra-high molecular weight polyethylene fused yarn of the present invention, a plurality of the ultra-high molecular weight polyethylene fused yarns as described above are knitted.

EFFECTS OF THE INVENTION

Since the ultra-high molecular weight polyethylene fused yarn of the present invention is excellent in fusibility, the ultra-high molecular weight polyethylene fused yarn is less likely to be separated into filaments. The ultra-high molecular weight polyethylene fused yarn has a monofilament shape, is easily drained, and is excellent in surface smoothness.

The ultra-high molecular weight polyethylene fused yarn of the present invention has excellent knot strength, and can be suitably used as, for example, a fishing line. Furthermore, a preferred ultra-high molecular weight polyethylene fused yarn of the present invention can be particularly suitably used as a fishing line because the knot strength is less likely to depend on a knotting method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view illustrating one form of an ultra-high molecular weight polyethylene multifilament.

FIG. 2 is a front view showing another form of an ultra-high molecular weight polyethylene multifilament.

FIG. 3 is a front view showing another form of an ultra-high molecular weight polyethylene multifilament.

FIG. 4 is a reference view illustrating an apparatus for manufacturing an ultra-high molecular weight polyethylene fused yarn.

FIG. 5 is a reference view illustrating a system of an impregnation device and an excess removing device.

FIGS. 6A and 6B are reference views illustrating a method for knotting a yarn when measuring knot strength.

EMBODIMENTS OF THE INVENTION

Hereinafter, the present invention will be described with reference to the drawings as appropriate.

In the present specification, in a case where a plurality of numerical ranges described as a lower limit value or more and an upper limit value or less are separately described, an optional lower limit value and an optional upper limit value are selected, and a numerical range of “an optional lower limit value or more and an optional upper limit value or less” can be set. In addition, “substantially” means a range acceptable in the technical field to which the present invention belongs.

Outline of Ultra-High Molecular Weight Polyethylene Fused Yarn

The ultra-high molecular weight polyethylene fused yarn of the present invention includes an ultra-high molecular weight polyethylene multifilament and a liquid paraffin, and the ultra-high molecular weight polyethylene multifilament is fused. One feature of the ultra-high molecular weight polyethylene fused yarn of the present invention is that it contains 15% by weight or more of the liquid paraffin having an average molecular weight of 400 or more. The fused yarn of the present invention containing a predetermined amount of the liquid paraffin having a predetermined molecular weight is excellent in the fusibility and forms a monofilament shape.

Here, the “ultra-high molecular weight polyethylene fused yarn” refers to a yarn produced by fusing each ultra-high molecular weight polyethylene monofilament constituting an ultra-high molecular weight polyethylene multifilament. The “ultra-high molecular weight polyethylene multifilament” refers to a state before each monofilament is fused, and the “ultra-high molecular weight polyethylene monofilament” refers to a long fiber made of ultra-high molecular weight polyethylene constituting the ultra-high molecular weight polyethylene multifilament. Hereinafter, “ultra-high molecular weight polyethylene” is referred to as “UHPE”.

UHPE Multifilament (UHPE Multifilament Before Fusion)

The UHPE multifilament is formed of a plurality of UHPE monofilaments.

The UHPE is polyethylene having an increased molecular weight, and is, for example, polyethylene having a molecular weight of 400,000 or more, and preferably polyethylene having a molecular weight of 600,000 or more. As the UHPE, one having a melting point of 140° C. or higher is used. The UHPE monofilament is a filament manufactured by so-called gel spinning of UHPE.

A tensile strength of the UHPE multifilament is 19.6 cN/dtex or more, preferably 24.5 cN/dtex or more and 49.0 cN/dtex or less, and more preferably 29.4 cN/dtex or more and 39.2 cN/dtex or less. As such a high-strength UHPE multifilament, a commercially available product can be used, for example. Examples of the commercially available product include “Dyneema” (trade name) available from DSM, “Spectra” (trade name) available from Honeywell, and “Izanas” (trade name) available from Toyobo Co., Ltd.

The tensile strength can be measured in accordance with JIS L 1013 (2010)-8.5.

A fineness of the UHPE monofilament is not limited to a particular fineness. When the fineness of the UHPE monofilament is excessively small, a gap between adjacent monofilaments in the multifilament becomes relatively small, and it becomes difficult to uniformly impregnate the inside of the multifilament with a liquid paraffin, so that the fusibility may be deteriorated. From such a viewpoint, the fineness of the UHPE monofilament is, for example, 0.5 dtex or more and preferably 1.0 dtex or more. On the other hand, when the fineness of the UHPE monofilament is excessively large, the gap between adjacent monofilaments in the multifilament becomes relatively large, and a bonding point (fusion) between the filaments per unit volume may be lowered. From such a viewpoint, the fineness of the UHPE monofilament is, for example, 5.0 dtex or less and preferably 4.0 dtex or less.

In the present specification, “tex” as a unit of fineness (thickness) is weight (in grams) per 1,000 m, and “dtex” as a unit of fineness (thickness) is weight (in grams) per 10,000 m. In the present invention, the fineness can be measured in accordance with JIS L 1013 (2010)-8.3.1-b) method B.

The UHPE multifilament includes a plurality of the UHPE monofilaments. The number of UHPE monofilaments constituting the UHPE multifilament is not limited to the particular number, and is, for example, 5 or more and 5,000 or less, and preferably 10 or more and 2,500 or less. The fineness of the UHPE multifilament is generally determined by the fineness of the UHPE monofilament×the number of UHPE monofilaments.

The UHPE multifilament may have a form in which a plurality of UHPE monofilaments constituting the UHPE multifilament are simply aligned, a form in which a plurality of UHPE monofilaments are aligned and twisted, or a form in which a plurality of UHPE monofilaments are knitted. The twisting may be either S-twisting (right-twisting) or Z-twisting (left-twisting). Examples of the knitted string include an aspect in which a plurality of filaments are alternately knitted, an aspect in which a plurality of filaments are knitted around a filament serving as a core material, and the like. The filament used for the knitted string may be twisted in advance.

FIG. 1 illustrates a UHPE multifilament 21 formed of a plurality of aligned UHPE monofilaments 3, FIG. 2 illustrates a UHPE multifilament 22 prepared by S-twisting the plurality of aligned UHPE monofilaments 3, and FIG. 3 illustrates a UHPE multifilament 23 prepared by Z-twisting the plurality of aligned UHPE monofilaments 3.

When the UHPE multifilament is twisted, a twist coefficient K1 is not limited to a particular value, and is preferably more than 0 and 5,500 or less, more preferably 1,000 or more and 5,000 or less, and still more preferably 2,000 or more and 4,500 or less. By using the UHPE multifilament having the twist coefficient K1 in the above range, a UHPE fused yarn having a knot strength ratio a/b in the range of 0.9 or more and 1.1 or less can be produced. The UHPE multifilament in which a plurality of UHPE monofilaments are simply aligned has a twist coefficient K1 of zero.

The twist coefficient K1 of the UHPE multifilament is determined by Equation 1: K1=t×D^(1/2). Here, t in the above Equation 1 represents the number of twists (times/m) of the UHPE multifilament, and D in the above Equation 1 represents the fineness (tex) of the UHPE multifilament.

Liquid Paraffin

A liquid paraffin is a colorless liquid paraffin under standard conditions (23° C., 1 atm, 50% RH). The liquid paraffin is an aggregate of mainly alkanes having 20 or more carbon atoms.

Note that mineral oil is a generic term for a mixture of hydrocarbon compounds derived from underground resources such as petroleum, natural gas, and coal and impurities. The liquid paraffin is different from the mineral oil in that alkane having 20 or more carbon atoms is purified.

In the present invention, the liquid paraffin having an average molecular weight of 400 or more is used, preferably the liquid paraffin having an average molecular weight of 420 or more is used, more preferably the liquid paraffin having an average molecular weight of 430 or more is used, and still more preferably the liquid paraffin having an average molecular weight of 450 or more is used. When a predetermined amount of such liquid paraffin is contained in the UHPE multifilament, a UHPE fused yarn having excellent fusibility can be produced. The upper limit of the average molecular weight of the liquid paraffin is not limited to a particular average molecular weight, but when the average molecular weight is excessively large, the fluidity is lowered, and there is a possibility that it becomes difficult to uniformly impregnate the inside of the multifilament (gap between the monofilaments) with the liquid paraffin. From such a viewpoint, the upper limit of the average molecular weight of the liquid paraffin is 800 or less, preferably 700 or less, more preferably 600 or less, and still more preferably 490 or less. As the liquid paraffin, for example, a commercially available product can be used. Examples of the commercially available product include “MORESCO WHITE” (trade name) available from MORESCO Corporation.

Here, the average molecular weight of a liquid paraffin can be calculated in terms of a normal paraffin from a calibration curve obtained using gas chromatography and the normal paraffin as a standard substance. A specific method for measuring the average molecular weight of a liquid paraffin is as described in the following examples.

Method for Manufacturing UHPE Fused Yarn

A method for manufacturing a UHPE fused yarn of the present invention includes, for example, a step of impregnating a UHPE multifilament with a liquid paraffin having an average molecular weight of 400 or more, and a step of heating and stretching the UHPE multifilament containing the liquid paraffin.

FIG. 4 is a reference view illustrating an example of a manufacturing apparatus 6 for a UHPE fused yarn. The arrow in FIG. 4 indicates the traveling direction of a UHPE multifilament 2 (the same applies to FIG. 5).

The UHPE multifilament 2, which is an original yarn, is loaded in a yarn withdrawal device 61. As described above, a twisted UHPE multifilament 2 may be loaded, or an untwisted UHPE multifilament 2 may be loaded. Between the yarn withdrawal device 61 and a first stretching device 62, the twisting may be applied to the UHPE multifilament 2. The UHPE multifilament 2 pulled out from the yarn withdrawal device 61 is stretched while being fed from the first stretching device 62 to a second stretching device 66. As the first and second stretching devices 62 and 66, for example, a stretching device including a plurality of rollers can be used. An impregnation device 63, an excess removing device 64, and a heating device 65 are disposed in this order between the first stretching device 62 and the second stretching device 66. The impregnation device 63 is configured to impregnate the UHPE multifilament 2 with a liquid paraffin. A method for impregnating a liquid paraffin is not limited to a particular method, and examples thereof include a method in which the liquid paraffin is applied to the UHPE multifilament 2 using a nonwoven fabric, a woven fabric, a brush, a sponge, or the like, the UHPE multifilament 2 is passed through a bath storing a liquid paraffin (dipping), and the liquid paraffin is sprayed onto the UHPE multifilament 2 using a spray or the like. The excess removing device 64 is configured to remove excess liquid paraffins from the UHPE multifilament 2 which has been impregnated with the liquid paraffin. The removal method is not limited to a particular method, and examples thereof include a method of wiping a liquid paraffin using a nonwoven fabric, a woven fabric or the like, and a method of removing a liquid paraffin on a surface of the UHPE multifilament 2 using a roller or the like. The heating device 65 is configured to apply heat to the UHPE multifilament 2 which has been impregnated with the liquid paraffin. The heating device 65 is not limited to a particular device, and examples thereof include an oven and the like.

FIG. 5 is a reference view illustrating an example of the impregnation device 63 and the excess removing device 64.

In the example of FIG. 5, the impregnation device 63 includes a supply unit 631 configured to supply a liquid paraffin, a storage unit 632 configured to store the liquid paraffin supplied from the supply unit 631, and an impregnation unit 633 configured to impregnate the UHPE multifilament 2 with the liquid paraffin stored in the storage unit 632. Portions where the liquid paraffin is present are illustrated by numerous dots.

The liquid paraffin is supplied from the supply unit 631 to the storage unit 632 so that a liquid level of the liquid paraffin in the storage unit 632 maintains a predetermined height. As the impregnation unit 633, a cloth-like body that can be impregnated with the liquid paraffin is used. Examples of the cloth-like body include a nonwoven fabric that can be impregnated with the liquid paraffin, felt, or a composite material of a nonwoven fabric and felt. One part of the cloth-like body is immersed in the liquid paraffin of the storage unit 632, and the opposite part of the cloth-like body is in contact with the UHPE multifilament 2. The liquid paraffin in the storage unit 632 is brought into contact with the UHPE multifilament 2 and impregnated into the UHPE multifilament 2 along the cloth-like body which is the impregnation unit 633. The impregnation unit 633 is configured such that a distance from the liquid level of the storage unit 632 to the UHPE multifilament 2, a contact area and a contact pressure (contact strength) of the cloth-like body with respect to the UHPE multifilament 2, and the like can be appropriately set. The amount of the UHPE multifilament 2 impregnated with the liquid paraffin can be adjusted by setting the above-mentioned items of the impregnation unit 633.

The excess removing device 64 is disposed on a downstream side of the impregnation unit 633. As the excess removing device 64, a cloth-like body capable of absorbing the liquid paraffin is used. Examples of the cloth-like body include a nonwoven fabric capable of absorbing the liquid paraffin, felt, or a composite material of a nonwoven fabric and felt. By winding such a cloth-like body around the UHPE multifilament 2, excess liquid paraffins of the UHPE multifilament 2 can be removed. The excess removing device 64 is configured so that the contact area and the contact pressure (contact strength) of the cloth-like body with respect to the UHPE multifilament 2 can be appropriately set. By setting the items of the excess removing device 64, the amount of excess liquid paraffins to be removed from the UHPE multifilament 2 can be adjusted.

The UHPE multifilament 2 pulled out from the yarn withdrawal device 61 is impregnated with the liquid paraffin having an average molecular weight of 400 or more and the excess is removed by the impregnation device 63 and the excess removing device 64. The amount of the liquid paraffin contained in the UHPE fused yarn as the final product can be set by appropriately adjusting the amount of the liquid paraffin impregnated into the UHPE multifilament 2 and the amount of the liquid paraffin removed. The UHPE multifilament 2 impregnated with the liquid paraffin is heated by a heating device 65. It is preferable to perform heating so that the temperature of the UHPE multifilament 2 falls within the range of 140° C. or higher and 158° C. or lower. After the heating, the UHPE multifilament 2 is stretched in a longitudinal direction by the second stretching device 66, whereby the UHPE fused yarn 1 can be produced. The produced UHPE fused yarn 1 is wound around a yarn winding device 67. By making the peripheral speed of the roller of the second stretching device 66 faster than the peripheral speed of the roller of the first stretching device 62, the UHPE multifilament 2 can be appropriately stretched. The stretch ratio is preferably in the range of 1.5 times or more and 2.5 times or less in order to preserve or increase the orientation of the molecular chains of UHPE.

In the illustrated example, a single-stage heating and stretching device has been exemplified, but the number of stretching stages, the number of heating devices, the length thereof, and the like can be appropriately changed.

UHPE Fused Yarn

The UHPE fused yarn contains the above-described UHPE multifilament and the above-described liquid paraffin having an average molecular weight of 400 or more, and the content of the liquid paraffin is 15% by weight or more. The content of the liquid paraffin is preferably 18% by weight, and more preferably 20% by weight or more. If the content of the liquid paraffin is excessively large, the liquid paraffin may ooze out on the surface of the UHPE fused yarn. From such a viewpoint, the content of the liquid paraffin is preferably 40% by weight or less, more preferably 35% by weight or less, and still more preferably 25% by weight or less.

Here, the content (%) of the liquid paraffin is determined by the content (% by weight)=(M−N)/N×100. M represents the weight per unit length of the UHPE fused yarn containing the liquid paraffin, and N represents the weight per unit length of the UHPE fused yarn produced by heat stretching without being impregnated with the liquid paraffin. A specific method for measuring the content of the liquid paraffin is as described in the following examples.

A single yarn fineness of the UHPE fused yarn is not limited to a particular single yarn fineness, but if the single yarn fineness is excessively small or large, the fusibility may be deteriorated. From such a viewpoint, the single yarn fineness of the UHPE fused yarn is preferably 0.7 dtex or more and 2.5 dtex or less, more preferably 0.7 dtex or more and 2.2 dtex or less, and still more preferably 1.0 dtex or more and 1.5 dtex or less.

The single yarn fineness of the UHPE fused yarn refers to a value determined by dividing the fineness of the UHPE multifilament (UHPE multifilament before fusion) by the stretch ratio and further dividing the resultant by the number of filaments.

When the UHPE multifilament is twisted, a twisted UHPE fused yarn is produced. In this case, the twist coefficient K2 of the UHPE fused yarn is not limited to a particular value, and is preferably more than 0 and 2,200 or less, more preferably 400 or more and 2,100 or less, and still more preferably 900 or more and 2,050 or less. The UHPE fused yarn having the twist coefficient K2 in the above range has a knot strength ratio a/b in a range of 0.9 or more and 1.1 or less. In the UHPE fused yarn having a knot strength ratio (a/b) of 0.9 or more and 1.1 or less, the superiority or inferiority of the yarn strength due to a knotting method is extremely small. The UHPE fused yarn having a knot strength ratio in such a range can be suitably used as a fishing line. The twist coefficient K2 of the UHPE fused yarn produced from the UHPE multifilament in a form in which a plurality of UHPE monofilaments are simply aligned is zero.

The twist coefficient K2 of the UHPE fused yarn is determined by Equation 2: K2=t×D^(1/2). t in Equation 2 represents the number of twists (times/m) of the UHPE fused yarn, and D in Equation 2 represents the weight (unit gram) of the fused yarn per 1,000 m in length, excluding the amount of the paraffin contained from the fused yarn. A specific method for measuring the twist coefficient K2 of the UHPE fused yarn is as described in the following examples.

The UHPE fused yarn of the present invention is excellent in fusibility. The fusibility refers to a degree to which the monofilaments constituting the UHPE multifilament before fusion are bonded to each other by fusion. The UHPE fused yarn having excellent fusibility has a monofilament shape. Therefore, the UHPE fused yarn of the present invention is excellent in water drainage and excellent in surface smoothness, is less likely to fluff even when cut, and is also excellent in abrasion resistance.

EXAMPLES

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

UHPE Multifilament Used

Multifilament (1): A UHPE multifilament prepared by aligning 96 UHPE monofilaments and having a fineness of 22.2 tex. Trade name “IZANAS” available from Toyobo Co., Ltd.

Multifilament (2): A UHPE multifilament prepared by aligning 192 UHPE monofilaments and having a fineness of 22.2 tex. Trade name “IZANAS” available from Toyobo Co., Ltd.

Multifilament (3): A UHPE multifilament prepared by aligning 120 UHPE monofilaments and having a fineness of 22.2 tex.

Multifilament (4): A UHPE multifilament prepared by aligning 64 UHPE monofilaments and having a fineness of 22.2 tex. Trade name “IZANAS” available from Toyobo Co., Ltd.

Multifilament (5): A UHPE multifilament prepared by aligning 32 UHPE monofilaments and having a fineness of 22.2 tex. Trade name “IZANAS” available from Toyobo Co., Ltd.

Auxiliary Agent Used

Liquid paraffin: 7 kinds of liquid paraffins having different average molecular weights indicated in Table 1, available from MORESCO Corporation.

Naphthenic base oil (mineral oil): Molecular weight of 348, available from Sankyo Oil Chemical Industry Co., Ltd.

Glycerin: Molecular weight of 92, available from Sakamoto Yakuhin Kogyo Co., Ltd.

Decalin: Decahydronaphthalene, molecular weight of 138, available from Kishida Chemical Co., Ltd.

Polyethylene glycol: Molecular weight of 400, available from Sanyo Chemical Industries, Ltd.

Vegetable oil: Coconut oil, average molecular weight is 200, available from COCOWELL CORPORATION.

Silicone oil: Silicone oil having molecular weights of 2,000 and 6,000, available from Shin-Etsu Silicone Co., Ltd.

Measurement of Molecular Weight of Auxiliary Agent

The average molecular weight of the liquid paraffin was calculated in terms of a normal paraffin from a calibration curve of the normal paraffin (Trade name “ASTM 5442 (C12-C60) Quantitative Linearity Standard” available from Sigma-Aldrich Co. LLC.) as a standard substance using a gas chromatograph (Trade name “GC-2010” available from Shimadzu Corporation).

Specifically, normal paraffin (Trade name “ASTM 5442 (C12-C60) Quantitative Linearity Standard” available from Sigma-Aldrich Co. LLC.) as a standard substance was measured by gas chromatography (Trade name “GC-2010” available from Shimadzu Corporation), and a calibration curve was prepared from a retention time of a peak value of the standard substance and the molecular weight of the standard substance.

Next, a liquid paraffin to be measured was similarly measured by gas chromatography. According to the principle of chromatography, the liquid paraffin moves to a detector with a retention time corresponding to the molecular weight, and then is converted into an electrical signal at the detector. A chromatogram was obtained by taking an elapsed time from the input of the sample on a horizontal axis and a signal intensity obtained from the detector on a vertical axis, and the retention time of a peak value of the signal intensity was measured. The molecular weight of the liquid paraffin to be measured was determined from the retention time of the peak value and the calibration curve.

An example of measurement conditions of the gas chromatograph is shown below.

Detector type: FID.

Column: Capillary column (Trade name “Ultra alloy-SIMDIS (HT)” available from Frontier Lab Corporation). Length: 10 m, Inner diameter: 0.53 mm, Film thickness: 0.1 μm.

Carrier gas: Helium gas. Flow rate: 24.0 (ml/min), Linear velocity: 140.5 cm/s.

Column initial temperature: 35° C. Rate: 10° C./min, Final temperature: 410° C., Detector temperature: 420° C.

Injection method: Total volume injection. Sample injection volume: 0.5 μl (microliters).

The average molecular weight of the coconut oil was also determined in the same manner as in the liquid paraffin.

The average molecular weight of the naphthenic base oil was calculated by an n-d-M method defined in ASTM D3238.

The molecular weights of glycerin and decalin were identified from the molecular formula.

The molecular weight of polyethylene glycol was calculated from mg per 1 mol of potassium hydroxide×the number of hydroxyl groups in polyethylene glycol/the hydroxyl value of polyethylene glycol. The hydroxyl value of polyethylene glycol is the number of milligrams of potassium hydroxide equivalent to the hydroxyl group in 1 g of polyethylene glycol.

The molecular weight of the silicone oil was calculated from the A. J. Barry equation (Logη=1.00+0.0123M^(0.5)). Here, η represents a kinematic viscosity (mm²/s) at 25° C., and M represents a molecular weight of the silicone oil.

Manufacturing Apparatus Used

As illustrated in FIG. 4, a manufacturing apparatus 6 including a yarn withdrawal device 61, a first stretching device 62, an impregnation device 63, an excess removing device 64, a heating device 65, a second stretching device 66, and a yarn winding device 67 in this order was used. The impregnation device 63 and the excess removing device 64 of the manufacturing apparatus 6 were of a type as indicated in FIG. 5. That is, the impregnation device 63 was a system of bringing a nonwoven fabric containing an auxiliary agent (a liquid paraffin or the like) into contact with the surface of the UHPE multifilament, and a removal system of the excess removing device 64 was a system of bringing a dried nonwoven fabric into contact with the surface of the UHPE multifilament. The impregnation device 63 includes a supply unit 631 configured to continuously supply an auxiliary agent to the nonwoven fabric, and a supply amount of the auxiliary agent to the nonwoven fabric can be optionally set by the supply unit 631. As the heating device, two ovens each having a length of 5 m of a radiation heat type were used, and as the stretching device, a one-step stretching method as illustrated in FIG. 4 was used.

Example 1

A multifilament (1) was loaded in the yarn withdrawal device 61 of the manufacturing apparatus 6 installed at room temperature (23° C.), and a liquid paraffin having an average molecular weight of 400 was supplied as an auxiliary agent to the impregnation device 63. The multifilament (1) was drawn out, and the liquid paraffin was applied to the multifilament, and the excess liquid paraffins were further removed from the multifilament (1). Thereafter, the multifilament (1) was subjected to a stretching treatment while being heated to about 155° C. to produce a UHPE fused yarn of Example 1. The peripheral speed of the first stretching device 62 was set to 10 m/min, and the peripheral speed of the second stretching device 66 was set to 17 m/min so that the stretch ratio was about 1.7 times.

Examples 2 to 7 and Comparative Examples 1 to 10

UHPE fused yarns of Examples 2 to 7 and Comparative Examples 1 to 10 were respectively produced in the same manner as in Example 1 except that the auxiliary agent was changed as indicated in Table 1. In Examples 2 to 7 and Comparative Example 3, a distance from the liquid level of the storage unit 632 (the liquid level of the liquid paraffin stored in the storage unit 632) to the multifilament and the contact pressure of the nonwoven fabric of each of the impregnation device 63 and the excess removing device 64 to the multifilament were changed from those in Example 1.

In Table 1, “MF” represents a multifilament, and “FY” represents a UHPE fused yarn (the same applies to Tables 2 to 4 below.).

TABLE 1 Compar- Compar- Compar- ative ative ative Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample ample ample 1 2 3 4 5 6 7 1 2 3 MF MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) Auxiliary Kind Liquid Liquid Liquid Liquid Liquid Liquid Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin paraffin paraffin paraffin paraffin paraffin paraffin (Average) 400 430 453 470 483 550 550 335 335 470 Molecular weight FY Content 21.9 20.0 22.0 15.3 19.1 23.2 36.6 11.0 20.9 13.6 (% by weight) Fusibility B A AA A AA A A D C C Single 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 yarn fineness (dtex) Tensile 31.4 31.5 30.6 31.8 34.3 32.4 26.1 36.2 30.6 33.4 strength (cN/dtex) Elongation 3.6 3.6 3.6 3.3 3.8 3.8 3.4 3.5 3.5 3.3 rate (%) Knot 11.4 12.7 11.5 13.1 12.0 12.3 10.1 13.2 11.4 12.7 strength a (cN/dtex) Elongation 1.1 1.2 1.2 1.2 1.1 1.2 1.2 1.1 1.2 1.1 rate a (%) Knot 12.3 12.0 11.1 13.8 12.9 12.8 10.6 13.5 12.1 12.9 strength b (cN/dtex) Elongation 1.2 1.2 1.1 1.3 1.2 1.3 1.2 1.1 1.2 1.1 rate b (%) Knot 0.92 1.06 1.04 0.95 0.93 0.96 0.96 0.98 0.95 0.98 strength ratio (a/b) Handle- Excellent Excellent Excellent Excellent Excellent Excellent Excellent Poor Poor Poor ability Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample 4 5 6 7 8 9 10 MF MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) MF(1) Auxiliary Kind Naphthenic Glycerin Decalin Polyethylene Vegetable Silicone Silicone agent base glycol oil oil oil oil (Average) 348 92 138 400 200 2000 6000 Molecular weight FY Content 16.2 15.0 0 29.4 18.0 20.0 18.8 (% by weight) Fusibility D D D D D D D Single 1.4 1.4 1.4 1.4 1.4 1.4 1.4 yarn fineness (dtex) Tensile 33.0 31.6 34.0 28.2 32.7 31.2 31.9 strength (cN/dtex) Elongation 3.1 3.4 3.3 3.0 3.5 3.3 3.2 rate (%) Knot 13.5 11.1 13.1 11.4 12.4 12.7 12.1 strength a (cN/dtex) Elongation 1.3 1.1 1.3 1.1 1.2 1.3 1.2 rate a (%) Knot 14.3 10.9 13.2 11.6 12.9 13.4 12.4 strength b (cN/dtex) Elongation 1.3 1.2 1.3 1.1 1.1 1.4 1.2 rate b (%) Knot 0.94 1.02 0.99 0.98 0.96 0.95 0.98 strength ratio (a/b) Handle- Poor Poor Poor Poor Poor Poor Poor ability

Measurement of Content of UHPE Fused Yarn

The content of the auxiliary agent contained in each UHPE fused yarn prepared in each of the examples and comparative examples was measured. Specifically, each UHPE fused yarn was cut out by 1 m, and the weight thereof was measured in units of 0.1 mg. Separately, a yarn (hereinafter, referred to as a control yarn) was prepared in the same manner as in Example 1 except that no auxiliary agent was applied, and 1 m of the control yarn was cut out, and the weight thereof was measured in units of 0.1 mg. Then, the content of the auxiliary agent such as a liquid paraffin was determined by substituting into the following formula. The results are indicated in Table 1.

Content (% by weight) of auxiliary agent in UHPE fused yarn=(M−N)/N×100.

Here, M represents the weight of the UHPE fused yarn of each of the examples and comparative examples, and N represents the weight of the control yarn.

Evaluation of Fusibility of UHPE Fused Yarn

The surface of each UHPE fused yarn prepared in each of the examples and comparative examples was visually observed, each fused yarn was strongly rubbed with a finger, the degree of fusion of the filament was evaluated, and whether or not the UHPE fused yarn was suitable as a fishing line was evaluated. The results are indicated in Table 1.

AA: The surface of the fused yarn was sufficiently smooth. Each monofilament was sufficiently fused, and the fused yarn was not separated. It can be very suitably used as a fishing line.

A: The surface of the fused yarn was sufficiently smooth. Each monofilament was sufficiently fused, and the fused yarn was hardly separated. It can be suitably used as a fishing line.

B: The surface of the fused yarn was smooth. A part (1 or 2 points per 100 m) of the fused yarn slightly came apart and was separated into several monofilaments. It can be used as a fishing line.

C: Some irregularities were observed on the surface of the fused yarn. Many parts (3 or more points per 100 m) of the fused yarn came apart and separated into several monofilaments in those parts. It may possibly be used as a fishing line.

D: Each monofilament constituting the multifilament was not fused, and each monofilament was separated at all portions, and did not form a fused yarn. It can be evaluated that it was not able to be used as a fishing line.

Measurement of Single Yarn Fineness of UHPE Fused Yarn

A single yarn fineness of each UHPE fused yarn prepared in each of the examples and comparative examples was determined. The results are indicated in Table 1.

The single yarn fineness of the UHPE fused yarn was determined from the following calculation formula.

Single yarn fineness of UHPE fused yarn=(G1/G2)/G3

Here, G1 represents the fineness of the multifilament (the multifilament before being fused), G2 represents the stretch ratio, and G3 represents the number of monofilaments in the multifilament.

For example, the single yarn fineness of the UHPE fused yarns of Examples 1 to 7 and Comparative Examples 1 to 10 using the multifilament (1) is (22.2 tex/1.7)/96=about 0.136 tex=about 1.36 dtex.

Measurement of Tensile Strength and Elongation Rate of UHPE Fused Yarn

A tensile strength and an elongation rate of each UHPE fused yarn prepared in each of the examples and comparative examples were measured in accordance with JIS L 1013 (2010)-8.5. The results are indicated in Table 1. The tensile strength and the elongation rate are also called tensile breaking strength and breaking elongation. The tensile strength can be evaluated to be more preferable as the numerical value is larger.

Measurement of Knot Strength of UHPE Fused Yarn and Elongation Rate at the Time of Knot

Knot strengths a and b of the UHPE fused yarns prepared in each of the examples and comparative examples were measured in accordance with JIS L 1013 (2010)-8.6. The results are indicated in Table 1. The knot strength a is the strength when the yarn is knotted according to the knotting method a) of JIS L 1013 (2010)-8.6, and the knot strength b is the strength when the yarn is knotted according to the knotting method b) of JIS L 1013 (2010)-8.6. For reference, a state of the knotting method a) is illustrated in FIG. 6A, and a state of the knotting method b) is illustrated in FIG. 6B.

It is calculated by the knot strength ratio (a/b)=knot strength a/knot strength b.

In addition, the elongation rates a and b when the UHPE fused yarns were knotted in the knotting method a) and the knotting method b) were measured in accordance with JIS L 1013 (2010)-8.5. The results are indicated in Table 1. The elongation rate a is an elongation rate when the yarns are knotted in the knotting method a) as measured in accordance with JIS L 1013 (2010)-8.5. The elongation rate b is an elongation rate when the yarns are knotted in the knotting method b) as measured in accordance with JIS L 1013 (2010)-8.5.

Evaluation of Handleability of UHPE Fused Yarn

The handling easiness when each UHPE fused yarn prepared in each of the examples and comparative examples was used as a fishing line was evaluated. The results are indicated in Table 1.

Excellent: When the fused yarn was used as a fishing line and a lure was cast, frictional resistance between a guide of a fishing rod and the fishing line was low, and the lure was able to be thrown farther. During casting at 100 times/day, the fishing line was not cut or entangled with the guide of the fishing rod.

Poor: When the fused yarn was used as a fishing line and a lure was cast, frictional resistance between a guide of a fishing rod and the fishing line was high, and the lure was not able to be thrown farther. During casting at 100 times/day, the fishing line was cut or entangled with the guide of the fishing rod once or more times.

As in Examples 1 to 7, the UHPE fused yarns containing 15% by weight or more of the liquid paraffin having an average molecular weight of 400 or more had good fusibility. Furthermore, the UHPE fused yarns (Examples 2 to 7) containing 15% by weight or more of the liquid paraffin having an average molecular weight of 430 or more had excellent fusibility, and in particular, the UHPE fused yarns (Examples 3 to 5) containing 15% by weight or more of the liquid paraffin having an average molecular weight of 450 or more and 500 or less had more excellent fusibility. In addition, from the comparison between Examples 2 to 5, the fused yarn containing 18% by weight or more of the liquid paraffin having an average molecular weight of 450 or more and 490 or less was particularly excellent in the fusibility.

It can be said that the closer the knot strength ratio (a/b) is to 1, the less the difference in the knotting method affects the knot strength in the fused yarn. In other words, it can be said that the closer the knot strength ratio (a/b) is to 1, the more the fused yarn (hereinafter, referred to as a fused yarn having isotropic knot strength) in which the knot strength does not depend on the knotting method. In general, when the knot strength ratio (a/b) is in the range of 0.9 or more and 1.1 or less, it can be said that the fused yarn has isotropic knot strength. Examples 1 to 7 were fused yarns having isotropic knot strength.

Examples 1 to 7 having good fusibility were excellent in handleability. It is presumed that the fused yarns of Examples 1 to 7 having good fusibility have a monofilament shape, are hardly separated, and are excellent in surface smoothness.

Example 8

A UHPE fused yarn of Example 8 was prepared in the same manner as in Example 5 except that the multifilament (2) was used instead of the multifilament (1).

Example 9

A UHPE fused yarn of Example 9 was prepared in the same manner as in Example 5 except that the multifilament (3) was used instead of the multifilament (1).

Example 10

A UHPE fused yarn of Example 10 was prepared in the same manner as in Example 5 except that the multifilament (4) was used instead of the multifilament (1).

Example 11

A UHPE fused yarn of Example 11 was prepared in the same manner as in Example 5 except that the multifilament (5) was used instead of the multifilament (1).

Measurement of Content of UHPE Fused Yarn and Evaluation of Fusibility and the Like

The content of the liquid paraffin contained in each of the UHPE fused yarns prepared in Examples 8 to 11 was measured in the same manner as in Example 1. In addition, the fusibility, single yarn fineness, tensile strength, elongation rate, knot strength, handleability, and the like of each UHPE fused yarn prepared in Examples 8 to 11 were also measured and evaluated in the same manner as in Example 1. The results are indicated in Table 2.

TABLE 2 Example 8 Example 9 Example 10 Example 11 MF MF(2) MF(3) MF(4) MF(5) Auxiliary Kind Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin (Average) 483 483 483 483 Molecular weight FY Content 21.3 20.8 20.0 18.6 (% by weight) Fusibility A AA A B Single yarn 0.7 1.1 2.0 4.0 fineness (dtex) Tensile 26.0 30.9 27.9 25.1 strength (cN/dtex) Elongation 2.9 3.3 3.0 3.2 rate (%) Knot strength 10.4 13.2 13.2 12.8 a (cN/dtex) Elongation 1.1 1.2 1.2 1.4 rate a (%) Knot strength 11.0 13.7 12.2 12.6 b (cN/dtex) Elongation 1.1 1.2 1.1 1.4 rate b (%) Knot strength 0.94 0.96 1.08 1.02 ratio (a/b) Handleability Excellent Excellent Excellent Excellent

From Examples 8 to 11, it was found that the single yarn fineness affected the fusibility. From the comparison between Examples 8 to 10 and Example 11, when the single yarn fineness was 0.7 dtex or more and 2.5 dtex or less, the fusibility was excellent, and when the single yarn fineness was 1.0 dtex or more and 1.5 dtex or less, the fusibility was particularly excellent.

Examples 12 to 16

The UHPE fused yarns of Examples 12 to 16 were prepared in the same manner as in Example 9 except that the multifilament (3) was S-twisted with a twist coefficient K1 indicated in Table 3 before loading the multifilament (3) into the yarn withdrawal device.

Examples 17 to 21

The UHPE fused yarns of Examples 17 to 21 were prepared in the same manner as in Example 5 except that the multifilament (1) was S-twisted with a twist coefficient K1 indicated in Table 3 before loading the multifilament (1) into the yarn withdrawal device.

Examples 22 to 26

The UHPE fused yarns of Examples 22 to 26 were prepared in the same manner as in Example 10 except that the multifilament (4) was S-twisted with a twist coefficient K1 indicated in Table 3 before loading the multifilament (4) into the yarn withdrawal device.

Comparative Examples 11 and 12

The UHPE fused yarns of Comparative Examples 11 and 12 were prepared in the same manner as in Example 9 except that the S-twisted multifilament (3) with a twist coefficient K1 indicated in Table 4 was used and the auxiliary agent was changed to the auxiliary agent indicated in Table 4.

Comparative Examples 13 and 14

The UHPE fused yarns of Comparative Examples 13 and 14 were prepared in the same manner as in Example 9 except that the S-twisted multifilament (3) with a twist coefficient K1 indicated in Table 4 was used.

Comparative Examples 15 and 16

The UHPE fused yarns of Comparative Examples 15 and 16 were prepared in the same manner as in Example 5 except that the S-twisted multifilament (1) with a twist coefficient K1 indicated in Table 4 was used and the auxiliary agent was changed to the auxiliary agent indicated in Table 4.

Comparative Examples 17 and 18

The UHPE fused yarns of Comparative Examples 17 and 18 were prepared in the same manner as in Example 5 except that the S-twisted multifilament (1) with a twist coefficient K1 indicated in Table 4 was used.

Comparative Examples 19 and 20

The UHPE fused yarns of Comparative Examples 19 and 20 were prepared in the same manner as in Example 10 except that the S-twisted multifilament (4) with a twist coefficient K1 indicated in Table 4 was used and the auxiliary agent was changed to the auxiliary agent indicated in Table 4.

Comparative Examples 21 and 22

The UHPE fused yarns of Comparative Examples 21 and 22 were prepared in the same manner as in Example 10 except that the S-twisted multifilament (4) with a twist coefficient K1 indicated in Table 4 was used.

Calculation of Twist Coefficient K2 of UHPE Fused Yarn

The twist coefficient K2 of each of the UHPE fused yarns prepared in Examples 12 to 26 and Comparative Examples 11 to 22 was calculated. The results are indicated in Tables 3 and 4. The results of the fineness of the UHPE fused yarn (the fineness of the UHPE fused yarn itself containing a paraffin) are also indicated in Tables 3 and 4 (this fineness is indicated immediately below the twist coefficient K2 in Tables 3 and 4.).

The twist coefficient K2 of the UHPE fused yarn was calculated by Equation 2: K2=t×D^(1/2). t in Equation 2 represents the number of twists (times/m) of the UHPE fused yarn, and D in Equation 2 represents the weight (g) of the UHPE fused yarn per 1,000 m in length, excluding the amount of the paraffin contained.

Specifically, a length of 10 cm was taken out from an optional position of the UHPE fused yarn, the UHPE fused yarn having a length of 10 cm was observed with an optical microscope, the number of twists was measured, and the number of twists t (turns/m) of the fused yarn was determined by converting the number of twists per 1 m. The weight D per 1,000 m of the length of the UHPE fused yarn excluding the paraffin amount was determined as follows. The fineness of the UHPE fused yarn was measured according to JIS L 1013 (2010)-8.3.1-b) method B. This fineness is the fineness of the UHPE fused yarn itself containing a paraffin (without removing a paraffin). Based on the content of the liquid paraffin of the fused yarn, the paraffin content of the fused yarn was calculated, and the weight per 1,000 m of the UHPE fused yarn excluding the paraffin content was determined by excluding the calculated paraffin content from the measured fineness. The twist coefficient K2 of the UHPE fused yarn was determined by substituting the obtained number of twists t and the weight D per 1,000 m into Equation 2.

Measurement of Content of UHPE Fused Yarn and Evaluation of Fusibility and the Like

The content, fusibility, single yarn fineness, and the like of each UHPE fused yarn prepared in Examples 12 to 26 and Comparative Examples 11 to 22 were measured and evaluated in the same manner as in Example 1. The results are indicated in Tables 3 and 4.

TABLE 3 Ex- Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample ample 12 13 14 15 16 17 18 19 MF Kind MF(3) MF(3) MF(3) MF(3) MF(3) MF(1) MF(1) MF(1) Twist 1098 2200 3138 4231 5310 1098 2200 3138 coefficient K1 Auxiliary Kind Liquid Liquid Liquid Liquid Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin paraffin paraffin paraffin paraffin (Average) 483 483 483 483 483 483 483 483 Molecular weight FY Twist 503 1008 1452 2028 2600 499 1021 1456 coefficient K2 Fineness 162 160 165 179 182 157 166 165 (dtex) Content 20.3 19.1 20.2 21.3 18.1 18.1 20.3 19.7 (% by weight) Fusibility AA AA AA AA AA AA AA AA Single 1.1 1.1 1.1 1.1 1.1 1.4 1.4 1.4 yarn fineness (dtex) Tensile 24.0 26.6 29.6 28.8 28.1 31.0 31.4 35.3 strength (cN/dtex) Elongation 3.4 3.6 3.5 3.4 2.9 3.2 3.3 3.3 rate (%) Knot 11.1 10.2 9.8 9.5 9.0 11.2 11.2 10.8 strength a (cN/dtex) Elongation 1.2 1.0 1.0 1.0 1.1 0.9 0.8 0.8 rate a (%) Knot 10.7 10.3 10.5 10.4 11.0 11.0 11.5 11.5 strength b (cN/dtex) Elongation 1.2 1.0 1.1 1.2 1.4 1.2 1.0 1.1 rate b (%) Knot 1.04 0.99 0.93 0.91 0.82 1.02 0.97 0.94 strength ratio (a/b) Handle- Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent ability Ex- Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample ample 20 21 22 23 24 25 26 MF Kind MF(1) MF(1) MF(4) MF(4) MF(4) MF(4) MF(4) Twist 4231 5310 1098 2200 3138 4231 5310 coefficient K1 Auxiliary Kind Liquid Liquid Liquid Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin paraffin paraffin paraffin (Average) 483 483 483 483 483 483 483 Molecular weight FY Twist 2019 2633 500 1012 1452 2002 2573 coefficient K2 Fineness 173 188 162 160 165 173 182 (dtex) Content 18.1 19.3 21.8 18.1 20.2 20.2 20.7 (% by weight) Fusibility AA AA AA A A A A Single 1.4 1.4 2.0 2.0 2.0 2.0 2.0 yarn fineness (dtex) Tensile 35.7 30.9 32.3 36.3 35.6 35.5 30.3 strength (cN/dtex) Elongation 3.1 2.7 3.6 3.6 3.6 3.2 2.7 rate (%) Knot 10.5 9.5 11.0 11.4 11.3 10.8 9.2 strength a (cN/dtex) Elongation 0.9 1.0 1.0 0.9 0.9 0.9 1.0 rate a (%) Knot 11.4 11.2 11.0 12.1 12.3 11.9 11.1 strength b (cN/dtex) Elongation 1.2 1.3 1.2 1.0 0.9 1.2 1.2 rate b (%) Knot 0.92 0.85 1.00 0.94 0.92 0.91 0.83 strength ratio (a/b) Handle- Excellent Excellent Excellent Excellent Excellent Excellent Excellent ability

TABLE 4 Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample 11 12 13 14 15 16 MF Kind MF(3) MF(3) MF(3) MF(3) MF(1) MF(1) Twist 1098 3138 1098 3138 1098 3138 coefficient K1 Auxiliary Kind Liquid Liquid Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin paraffin paraffin (Average) 335 335 483 483 335 335 Molecular weight FY Twist 503 1452 503 1452 499 1456 coefficient K2 Fineness 149 152 151 153 148 154 (dtex) Content 10.4 10.6 11.7 11.3 11.8 11.2 (% by weight) Fusibility D D C C D D Single 1.1 1.1 1.1 1.1 1.4 1.4 yarn fineness (dtex) Tensile 32.2 31.1 29.0 27.2 33.0 33.2 strength (cN/dtex) Elongation 3.6 3.5 3.4 3.4 3.3 3.2 rate (%) Knot 12.7 9.7 11.1 9.5 11.8 9.3 strength a (cN/dtex) Elongation 1.1 1.1 1.2 1.1 1.0 0.9 rate a (%) Knot 12.4 10.3 11.2 9.8 11.8 9.8 strength b (cN/dtex) Elongation 1.2 1.1 1.2 1.0 1.1 1.0 rate b (%) Knot 1.02 0.94 0.99 0.97 1.00 0.95 strength ratio (a/b) Handle- Poor Poor Poor Poor Poor Poor ability Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative Ex- Ex- Ex- Ex- Ex- Ex- ample ample ample ample ample ample 17 18 19 20 21 22 MF Kind MF(1) MF(1) MF(4) MF(4) MF(4) MF(4) Twist 1098 3138 1098 3138 1098 3138 coefficient K1 Auxiliary Kind Liquid Liquid Liquid Liquid Liquid Liquid agent paraffin paraffin paraffin paraffin paraffin paraffin (Average) 483 483 335 335 483 483 Molecular weight FY Twist 499 1456 500 1452 500 1452 coefficient K2 Fineness 148 154 148 152 147 152 (dtex) Content 11.3 11.5 10.7 10.3 10.0 10.5 (% by weight) Fusibility C C D D C C Single 1.4 1.4 2.0 2.0 2.0 2.0 yarn fineness (dtex) Tensile 30.8 32.3 35.7 33.3 34.4 33.1 strength (cN/dtex) Elongation 3.3 3.1 3.5 3.5 3.3 3.3 rate (%) Knot 11.0 9.6 11.2 9.6 11.2 11.3 strength a (cN/dtex) Elongation 1.0 0.9 1.0 1.0 1.0 1.1 rate a (%) Knot 11.3 10.4 11.2 10.2 11.5 12.1 strength b (cN/dtex) Elongation 1.1 1.1 1.3 1.0 1.2 1.0 rate b (%) Knot 0.97 0.93 1.00 0.94 0.97 0.93 strength ratio (a/b) Handle- Poor Poor Poor Poor Poor Poor ability

Each of the UHPE fused yarns prepared in Examples 12 to 26 is excellent in fusibility and has good tensile strength and elongation rate. However, in Examples 15, 20, and 25 in which the twist coefficient K2 was about 2,000, the knot strength ratio was in the range of 0.9 or more and 1.1 or less, whereas in Examples 16, 21, and 26 in which the twist coefficient K2 was more than 2,500, the knot strength ratio was out of the above range. Based on the above, it is considered that a fused yarn having isotropic knot strength can be produced by setting the twist coefficient K2 to 2,200 or less.

As in Comparative Examples 11 to 22, when the average molecular weight of the liquid paraffin was less than 400 and/or the content thereof was less than 15% by weight, fusibility was poor and the liquid paraffin was not able to be used as a fishing line.

In Examples 12 to 26, S-twisted multifilaments were used. If the Z-twisted multifilaments are used, it is estimated that the values of the knot strength a and the knot strength b are reversed from the corresponding values in the case of S-twisting.

Example 27

The UHPE fused yarn prepared in Example 14 was cut to a length of about 300 m to prepare four UHPE fused yarns. The four fused yarns of Example 14 were knitted into a string shape to prepare the UHPE fused yarn of Example 27. The knot strength a and the knot strength b of the UHPE fused yarn of Example 27 were measured in the same manner as in Example 1. As a result, the knot strength ratio (a/b) of Example 27 was 0.95.

Example 28

The UHPE fused yarn prepared in Example 19 was cut to a length of about 300 m to prepare four UHPE fused yarns. The four fused yarns of Example 19 were knitted into a string shape to prepare the UHPE fused yarn of Example 28. The knot strength a and the knot strength b of the UHPE fused yarn of Example 28 were measured in the same manner as in Example 1. As a result, the knot strength ratio (a/b) of Example 28 was 0.99.

Example 29

The UHPE fused yarn prepared in Example 24 was cut to a length of about 300 m to prepare four UHPE fused yarns. The four fused yarns of Example 24 were knitted into a string shape to prepare the UHPE fused yarn of Example 29. The knot strength a and the knot strength b of the UHPE fused yarn of Example 29 were measured in the same manner as in Example 1. As a result, the knot strength ratio (a/b) of Example 29 was 0.92.

The fused yarns of Examples 27 to 29 were fused yarns having isotropic knot strength. In addition, even when these fused yarns were strongly rubbed with a fingertip, fluffing did not occur.

INDUSTRIAL APPLICABILITY

The ultra-high molecular weight polyethylene fused yarn of the present invention can be used as fishing materials such as a fishing line for leisure or fishery, a fishing net, or a longline; industrial materials such as ropes and twines; sports materials such as guts for tennis rackets and bowstrings; materials for musical instruments such as strings of a guitar; yarns forming protective clothing; and the like. In particular, the ultra-high molecular weight polyethylene fused yarn of the present invention can be suitably used as a fishing line for leisure or fishery.

DESCRIPTION OF REFERENCE SIGNS

1: Ultra-high molecular weight polyethylene fused yarn

2, 21, 22, 23: Ultra-high molecular weight polyethylene multifilament

3: Ultra-high molecular weight polyethylene monofilament

6: Apparatus for manufacturing fused yarn 

1-6. (canceled)
 7. An ultra-high molecular weight polyethylene fused yarn comprising: an ultra-high molecular weight polyethylene multifilament, wherein the fused yarn includes a liquid paraffin having an average molecular weight of 400 or more in an amount of 15% by weight or more.
 8. The ultra-high molecular weight polyethylene fused yarn according to claim 7, wherein the liquid paraffin has an average molecular weight of 430 or more.
 9. The ultra-high molecular weight polyethylene fused yarn according to claim 7, wherein the liquid paraffin has an average molecular weight of 450 or more and 490 or less.
 10. The ultra-high molecular weight polyethylene fused yarn according to claim 7, wherein a single yarn fineness of the fused yarn is 0.7 dtex or more and 2.5 dtex or less.
 11. The ultra-high molecular weight polyethylene fused yarn according to claim 8, wherein a single yarn fineness of the fused yarn is 0.7 dtex or more and 2.5 dtex or less.
 12. The ultra-high molecular weight polyethylene fused yarn according to claim 9, wherein a single yarn fineness of the fused yarn is 0.7 dtex or more and 2.5 dtex or less.
 13. The ultra-high molecular weight polyethylene fused yarn according to claim 7, wherein the fused yarn is twisted with a twist coefficient of more than 0 and 2,200 or less.
 14. The ultra-high molecular weight polyethylene fused yarn according to claim 8, wherein the fused yarn is twisted with a twist coefficient of more than 0 and 2,200 or less.
 15. The ultra-high molecular weight polyethylene fused yarn according to claim 9, wherein the fused yarn is twisted with a twist coefficient of more than 0 and 2,200 or less.
 16. The ultra-high molecular weight polyethylene fused yarn according to claim 10, wherein the fused yarn is twisted with a twist coefficient of more than 0 and 2,200 or less.
 17. The ultra-high molecular weight polyethylene fused yarn according to claim 7, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 18. The ultra-high molecular weight polyethylene fused yarn according to claim 8, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 19. The ultra-high molecular weight polyethylene fused yarn according to claim 9, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 20. The ultra-high molecular weight polyethylene fused yarn according to claim 10, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 21. The ultra-high molecular weight polyethylene fused yarn according to claim 11, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 22. The ultra-high molecular weight polyethylene fused yarn according to claim 12, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 23. The ultra-high molecular weight polyethylene fused yarn according to claim 13, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 24. The ultra-high molecular weight polyethylene fused yarn according to claim 14, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 25. The ultra-high molecular weight polyethylene fused yarn according to claim 15, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted.
 26. The ultra-high molecular weight polyethylene fused yarn according to claim 16, wherein a plurality of the ultra-high molecular weight polyethylene fused yarns are knitted. 